SANFORD, Florida (AP) -- Trayvon Martin's supporters fought for weeks to win an arrest after the 17-year-old black teenager was fatally shot by a neighborhood watch volunteer in Florida. Now George Zimmerman's attorney has begun what could be a lengthy legal battle to free his client from the second-degree murder charge filed in a case that has sparked outrage across the United States.
The first step for Zimmerman attorney Mark O'Mara will be to try to get his client out of jail while the legal process continues. A hearing for the 28-year-old probably will be held on April 20 to determine if he will be allowed to post bail and leave jail, O'Mara said late Thursday.
Earlier Thursday, Zimmerman stood straight and held his shaved head high during a four-minute hearing at a jailhouse courtroom while prosecutors briefly outlined their murder case in court papers.
O'Mara said his client's appearance and demeanor belies what he is going through.
"He is tired. He has gone through some tribulations," said O'Mara after the court appearance. "He is facing second-degree murder charges now. He is frightened. That would frighten any of us."
Zimmerman did not enter a plea during the hearing, although O'Mara previously said his client ultimately will plead not guilty. Zimmerman will be able to enter a plea during his May 29 arraignment.
At some point soon, O'Mara also is expected to ask the judge for a hearing on Florida's "stand your ground" self-defense law, which gives people a broad right to use deadly force without having to retreat from a fight.
"It is going to be a facet of this defense, I'm sure," he said in an interview. "That statute has some troublesome portions to it, and we're now going to have some conversations and discussions about it as a state. But right now it is the law of Florida and it is the law that is going to have an impact on this case."
For all the relief among civil rights activists over the arrest, legal experts warned there is a real chance the case could get thrown out before it ever goes to trial because of the "stand your ground" law.
At a pretrial hearing, Zimmerman's lawyers would only have to prove by a preponderance of evidence -- a relatively low legal standard -- that he acted in self-defense in order to get a judge to toss out the second-murder charges. And if that fails and the case does go to trial, the defense can raise the argument all over again.
To prove second-degree murder, prosecutors must show Zimmerman committed an "imminently dangerous" act that showed a "depraved" lack of regard for human life. The charge carries a mandatory sentence of 25 years in prison and a maximum of life.
Toward that, prosecutors said in an affidavit filed in support of the second-degree murder charge that on the night Zimmerman fatally shot Martin, Zimmerman followed and confronted the black teenager after a police dispatcher told him not to.
The brief outline appeared to contradict Zimmerman's account of events of the Feb. 26 evening -- that Martin attacked him after he had turned away and was returning to his vehicle.
In the affidavit, prosecutors also said Martin's mother identified cries for help heard in the background of a call to police as her son's. There had been some question as to whether Martin or Zimmerman was the one crying out.
The special prosecutor in the case, Angela Corey, has refused to explain exactly how she arrived at the charge. But in the affidavit, prosecutors said Zimmerman spotted Martin while patrolling his gated community, got out of his vehicle and followed the young man.
"Zimmerman, who also lived in the gated community, and was driving his vehicle observed Martin and assumed Martin was a criminal," the affidavit said, adding Martin was unarmed and was not committing a crime.
Prosecutors interviewed a friend of Martin's who spoke to him over the phone moments before the shooting. His parents' lawyer has said Martin was talking to his girlfriend back in Miami.
"During this time, Martin was on the phone with a friend and described to her what was happening," the affidavit said. "The witness advised that Martin was scared because he was being followed through the complex by an unknown male and didn't know why."
During a recorded call to a police dispatcher, Zimmerman "made reference to people he felt had committed and gotten away with break-ins in his neighborhood. Later while talking about Martin, Zimmerman stated `these a------s, they always get away' and also said `these f-----g punks,' said the affidavit, available at http://apne.ws/Itn7Nu.
It continued: "When the police dispatcher realized Zimmerman was pursuing Martin, he instructed Zimmerman not to do that and that the responding officer would meet him. Zimmerman disregarded the police dispatcher and continued to follow Martin who was trying to return to his home."
"Zimmerman confronted Martin and a struggle ensued," prosecutors said in their account.
Zimmerman told authorities Martin attacked